Railway traffic controlling system



July 19, 1932- W. BAUGHMAN 1,867,724

RAILWAY TRAFFIC CONTROLLING SYSTEM Filed 1360.5. 1930 2 sheets-sheet 1 /Q/-w ATTORNEY.

A G a l w52 3 R@ Patented July 19, 1932 ittica GEORGE W. BAUGHMAN, `or PITTSBURGH, PENNSYLVANIA, iissrefNoR` To Tirza UNION SWITCH & SIGNAL ooMrANY, or sWIssvALE," PENNSYLVANIA, a CORPORATION or rnNNs YLWI'NIaV RAILWAY TRAFFIC cNTRoLLING sYsTEM i Application filed 4December 5,1930..k Serial No. 590,314.A

My invent-ion relatesto railway traliic controlling systems ofthe codedtrack circuit type. One Afeature of my, invention is the provision of novel and improved coding and decoding apparatus for use in systems of this type.

I will describe certain forms of apparatus embodying my invention, and will then point `out the novel vfeatures thereof in claims.

In the accompanying drawings. Fig. lis a diagrammatic view of one form of decoding apparatus embodying my invention. Fig. 2 is a diagrammatic view yshowing one form of coding apparatus embodying my invention. Fig. 3 is a diagrammatic view of a modified form of decoding apparatus also embodying my invention. similar reference characters'refer to similar parts in all views. y s

ln accordance with, myl present invention, an alternating current of a given frequency is periodically interrupted orcoded into `impulses of equal duration. These impulses are arranged into groups each having a given number of impulses. The groups vare separated by an impulse or on period of the alternating current that is of much longer duration than the duration of Ya single -impulse 'of thegroup. Each particularcode is therefore distinguished by the number `of short impulses between two long impulses. Assuming that an alternating current of 100 cycles-is periodically interrupted or coded 180 times perfminute-that is, three cycles per second, then each. cycle consistszof an on periodduringwhich current flows, and the off period during lwhichno current flows. which is 1/3 secondy in duration. l I shall assumethroughout this description that the long impulse that separates a; group of such short impulses isof 0.5' second duration. One code of my invention will=have a group that consists of. twofull cyclesv of the 180 code impulses followed by an impulse of the4 '1 0.5Y second duration and vthis arrangement short impulses followed by: a vlong `impulse n the drawings,

and this group when consecutively repeated will establish a second and different indication. A third code may consist of ka group ofvv four complete cyclesof the'short impulses followedlby a long impulse and this group when consecutively repeated establishes a still diferent indication.V Likewise other groupsof impulses can be provided to establish other indications.. In one form of my invention here disclosed I propose to employ a code of two full cycles of the short impulses followed by the long impulse to estabish a caution or approach signal indication; a code of three full cycles of the short impulses followed by the long impulse to establish an approach restricted signal indication; and a code of fourcycles ot .a short impulse followed by a longimpulse to estab.-v lish aV proceed signal indication.V Y

It is Vapparent that inv such an arrangement, a large number of different indications can readily be established. Furthermore by utilizing a second and different frequency other thanthe 180 assumed7 say a frequency of 12() cycles per minute, thenstill other indications can readily be established without greatly increasing the apparatus required.

While in this description a codefrequency of 180 cycles per minute is assumed and the long impulse taken as being of 0.5 second duration and these impulses grouped asmentioned aboveto produce certain indications7 it will be understood that some other grouping ofthe impulses can be used and that the dura-i tion .of a long .impulse can be something m other than0-5 second without departing from the spirit and scope of my invention.

As a matter of fact inthe second form of the apparatus here` disclosed Vin the Fig. 3,

the short impulses when notarranged in groups are utilized to establish the approach indication, while a group of two full cycles of short impulses separated by a long iinpulse establishes V.an-approach restricted indication, and a group ofthree cycles of'short impulses followedby a long impulse establishes a proceed indication.y Vthere train carried apparatus is set to establish a proceed indication only after a certain V definite number of short impulsesof a given frequency y:as

is followed by a long impulse of a predetermined duration, a false indication, due to shock excitation when operating on an electric road or when the train is operating over non-coded alternating current track circuits, is a very remote possibility.

Referring to Fig. 1, the decoding apparatus, which as here shown is located on a train, includes two magnetizable cores 12 and 13 located in advance of the first pair of wheels, as is the practice in train contro-l'systems of this character.l The cores 12 and 13 are disposed in inductive relation with the two track rails X and Y. rIhe core 12 is provided with the winding 14 and the core 13 is provided with a similar winding 15 and the two windings 14 and 15 are connected in series so that voltages induced therein by an alternating current iowing in;opposite directions in the two track rails at any given instant are additive. These two windings Yare connected preferably through an amplifying device indicated by the reference character 16 with a controlling relay designated by the referencevcharacter MR and which relay I shall speak of as the master relay.

This master relay MR is preferably of the direct current polarized type, commonly employed in code .systems of train control, having a polarized armature 9 that remains in the position to which it was last moved until the relay is energized with reverse polarity. As is the usual practice in code systems, the electromagnet of the master relay MR is controlled by the amplifying device in a manner such that the building up of energy induced in the cores 12-13 creates an impulse of current in the electromagnet of the relay MR which is of a polarity that will position the polarized armature 9 in the righthand position-that is, the position as shown in the Fig. 1. The dying away of the energy induced in the cores 12-13 creates a current impulse in the electromagnet of the relay MR which is of a polarity that positions the polarized armature 9 in the left-hand positionthat is, a position reversed to that shown in the Fig. 1.

It follows then that each time the cores 12-13 become energized as the result of an alternating current impulse flowing in the rails X and Y, an'impulse of energy is supplied to the electromagnet of the relay MR, the polarity of which is such that the polarized armature 9 is positioned in the righthand position. Each time the cores 12-13 become deenergized as the result of a period during which no current flows in the rails, X and Y, an impulse is` supplied to the electromagnet of the relay MR of a polarity which positions the polarized armature 9 in the left-hand position. In the. event there is a prolonged period during which current is steadily induced in the cores 12 and 13, the polarized armature 9 remains in the right-hand position and in the event there is a prolonged period during which no current flows in the rails X and Y, the polariz-ed armature 9 remains in the left-hand position. In other words, thismaster relay MR is a polarized relay which is energized alternately in opposite directions in step with the energizing and deenergizing of the cores 12-13. Y'

The relay MR controls two slow-releasing l relays 1A and 1 in such'a manner that these ^relaysiare valternately energized when the master relay MR is energized alternately, in opposite directions. That is to say, when the armature 9 .swings to the left-hand, the

relay 1A is energized by current from the positive terminal B of a train carried source that is not vshown in the Fig. 1, through armature 9, wire 17, winding of relay 1A and to the negative terminal Cof the source of,

current. With armature 9 next swinging to the right-hand position, the relay 1 becomes energized by current from the positive terminal B through thearmature 9 in the righthand position, wire 18, armature 19 of the re- 1 lay 1A now in its raised'position, wire 20, winding of relay 1 and to the negative terminal C. Vith the armature 9 alternately swinging between its two positions, these two slow-releasing relays 1A and 1 are 1e and 24 drop. Also, if the relay 1A remains deenergized for a period greater than the release period of relay 1, the armatures of the relay 1 drop.

The slow-releasing relays 1A and 1 with the master relay MR control a series or chain of relays designated in the Fig. 1 by the reference character 2A, 2, 3A, 3, 4A, 4 and 5A. These relays are adapted to be arranged into groups. For illustration, they relays 1AQ1, 2A and 2 for a group that is used under kcertain conditions as will presently appear. The relays 1A, 1, 2A, 2, 3A and 3 form a second group that is used under certain other conditions. The relays 1A to 4; inclusive forms a third group that is used under still other conditions, and the Vrelays 1A to 5A inclusive form a fourth group active at times. Vhile the above group of relays are deemed sufficient to fully disclose my invention, ad-

ditional relays to form additional groups i" can be readily provided when the occasion demands. Y D

- On the first movement of the armature 9 to the left, the relay 1A picks up, and then astheV armature 9-swings back to the right- Pia hand, the relay 1 picks up in the manner previously pointed out. On the second movement of the armature 9 to the left, the relay 2A picks `up by current supplied from the positive terminal B through the armature'9, armature 23 of relay 1, back .contact 01"" the armature of the relay 2, wire 26, winding of. relay 2A and to the negative terminal C. During the .intervalthe armature 9 occupies this left-hand positionV after relay 2A picks up, the relay 2 has both terminalsV of its Winding connected to the positive terminal of the source of current, but as soon as the armature 9 swings to the right-hand position, the relay '2 picks up by current supplied from the positive terminal E, through armature 85 of the relay 1, wire 27, winding `of relay 2, wire 28, armature 29, winding of relay 2A. and to the negative terminal C. As long as Ythe relay'l is now retained energized, these two relays 2A and 2 are energized by the circuit that includes the coils of the relays in series. On the third movement of the armature 9 to the left, the relay 3A is picked up by the circuit from the positive terminal B, armature 9, armature 23,

armature 25, back contact of the armature of the relay 3, winding of the relay 3A and to the common terminal C. is the armature 9 next swings to the right, the relay 3 is picked up by the circuit through armature 32 in a manner similar to that just described for the relay 2. From this point on the relays 3A and 3 are retained energized as long as the relay 1 remains energized; On the fourth movement ot the armature 9 to the left, the relay 4A is picked up by the circuit from the positive terminal B through the armature 9 and the armatures 23, 25 and 30 and the back contact of the armature 86 of the relay 4. Then on thenext swing of the armature 9 to the right, the relay 4 is picked up by the circuit through armature in a manner similar to that pointed out for the relay 2 and fromrthis point on, the relays 4A.

and 4 remain energized as long as the relay 1 is energized. On the fifth movement ofthe armature 9 to the left, the relay 5A is picked up by a circuit that includes armatures 23, 25, 30 and 86 as will be readily understood by an inspection of the Fig. 1 and once relay 5A is up, it is retained energized by a circuit supplied with current from the positive terminal B through the armatureof the relay 1 and the front contact or" its own armature 36. It `follows that'from this point on, the operation of the armature 9 of the master relay MR to periodically energize the relays 1A ,and 1 results in the group of relays 2A-2, 3ft-3, .1.A--4, and 5A being retained energized. That is to-say that as long as armature 9 continues to swingV between its two positions in step withthe code impulses that are alternately energizing and deenergizing the cores 12'and 13, the chain of relays shown in Fig. 1 is energized. These relays controlvtraitic governing relays designated by the reference characters L, R and A. TWith the relays 1A to 5A inclusive energized in the manner above described, it is apparent from an inspection of the Fig. 1, that the relays L, R and A are each on open circuit, their control circuits being open at the back contact ot the armature 21 of the relay 1A. Also, the circuit is open at the back contact of the armature 37 ot the relay 5A for the relay A, and at the back contact ot the armature 38 of the relay 4'or the relay R, and at the back contact of the armature 39 oi the relay 3 for the relay L. Under this deenergized condition of the relays L, R and A, a circuit is closed to the cab indicator light 40 from the positive terminal B through the back contacts of the armatures 41, 42 and 43 respectively. ln the event the chain of relays 1A to 5A inclusive are all deenergizeddueto non-operation of the master relay MR, n

it is apparent that the trallic governing relays L, R and A are likewise all deenergized, their control circuit being open this time at the armature 24 of relay 1 and armature 87 of relay 2. Thus in Fig. 1 a continuous repeating of the 180 code impulses, or a failure et power, produce thesame cab indication, namely that displayed by the cab signal 40.

Let us new consider the case where at the end ci four complete cycles of short impulses, there rollo-ws an on period that is made long by thc addition of a 0.5 second impulsethat is, this impulse is approximately 0.5 second plus the normal onnperiod Starting Jfrom the dying away of a long impulse the first code cycle results in a movement of the armature 9 to the left and then back to the right, during which time the relays 1A and 1 pick up in the manner previously described. During the second complete code cycle, the armature 9 makes its second movement to the left and back to the right and this second movement results in relays 2A and 2 being picked up in the'manner abovedescribed. During the third cycle, the armature 9 makes its third movement to the left and back to the right and the relays 3A and 8 are picked up. Likewise during thel fourth l" code, the armature 9 makes its fourth movement and the'relays 4A and 4 are picked up. y

llhe next code on period being prolonged by the addition of a lone impulse, the armature ergy from each of the group of relays, namely 2A2, 3A-3, and 4A-4 and these relays then become deenergized. At the dying away of the long impulse, armature 9 swings to the left and the relay 1A is again energized and during the next four cycles of the short impulses, the chain of relays 1 to 4 inclusive are again energized which is then followed by the relays all being again deenergized at the next long impulse. This action of energizing this group of relays and then deenergizing them is consecutively repeated as long as this Code of four short impulses followed by a long impulse remains in effect. The result of this action is that a circuit to the traflic governing relay A is closed during the time relay 1A is down and the remaining relays are up. Looking at Fig. 1, as soon asthe relay 1A drops, and before the remaining relays 1 to 4A, inclusive, are deenergized, a circuit is closed from positive terinal B through the back contact of the armature 21 of relay 1A, front contact of the armature 24 of the relay l, front contact of the armature S7 of the rela-y 2, front contact of the armature 39 of the relay 3, front contact of the ari'nature 33 of the relay 4, back Contact of the armature 37 of the relay 5A, coil of the relay A and to common terminal C. lilith the relay A energized, then a circuit is established to the cab indicator through the front contact of the armature 41 of the relay A. The relay A is slow-releasing and its release period is made greater than the total time consumed by the group of four short impulses plus thelong impulse. It follows then that relay A remains up and the cab indicator 45 continuously displayed as long as the code consisting of groups of four short impulses separated by a long impulse remains in effect.

n the event the code consists of a group of but three complete cycles of the short impuls-es between successive long impulses, it is apparent that the relays lA and l will be picked up on the first cycle, the relays 2A and 2 picked up on the second cycle and relays 3A and 3 on the third cycle, and then this group of relays deenergized during the long impulse. Under this condition, the traffic governing relay R is energized during the interval thel relay 1A is down and the remaining relays 1, 2 and 3 are up, the circuit being from the positive terminal B through the back contact of the armature 21, armature 24 up, armature 87 up, armature 39 up and the armature 38 of the. relay 4 down, coil of relay R and to common terminal C. The relay R is slow-releasing and its release period is greater than the combined time consumed by a group of three short impulses plus the long impulse. With the armature 42 of the traiic governing relay R up, then current is supplied to the cab indicator 46 by a circuit from the -positive terminal B through the back contact of the armature 41 of relay A and a front contact of the armature 42 of the relay R.

In the event that the code consists of a .group of two short impulses between two successive long impulses, then the relays 1A and 1 are energized during the first cycle and the relays 2A and 2 energized during the second code cycle and then all deenergized during the long period. This operation results in the traffic governing relay L being energized during the interval that the relay V1A is down and the relays 1 and 2 are up, the circuit including the back contact of armature 21, front contact of armatures 24 Vand 87 and back contact of armature 39. Relay L is a slow-releasing' relay having a release period greater than the time consumed by the group of two short impulses plus a long impulse. With the relay L energized so as to raise its armature 43, a circuit is completed to the cab indicator 47. To sum up the operation thus far, the train carried apparatus of F ig. 1 establishes a different cab signal for each of the different codes cited.

Referring to Fig. 2, the track rails X and Y are arranged in track sections only one of which is shown. Normally traflic through the'section is in the direction indicated by the arrow. Each track section is provided with a. track relay TR which is connected across the track rails X and Y at the entrance end of the section. Normally an alternating current of a convenient frequency such as 100 cycles per second is supplied to the track relay by a track transformer Tv located at the exit end of the section, the secondary 48 of the transformer T being connected across the track rails X and Y through the usual current limiting reactor 49. The primary 50 of the track transformer T is connected to the secondary 51 of a line transformer N whose primary 52 is supplied with energy from a generator G over the transmission line E. The connection from the secondary 51 of the line transformer N to the primary 50 of the track transformer T includes a front contact of the armature 53 of a code transmitting relay CT. Normally this relay CT is retained energized by current from the positive terminal B of a convenient source of current but which is not shown in F ig. 2, back contact of an armature 54 of an approach energizing lrelay AP to be shortly described, wire 55, winding of the relay GT, wire 56 and to the negative terminal C. The approach energizing relay AP is normally deenergized, its circuit being normally open at the back contact of armature 57 of the track relay TR. This circuit for the relay AP is further controlled in a manner to be shortly pointed out.

Each track section of my invention is provided with relays designated by the reference characters HR, DR and ADR. These relays Vto respond to traic conditions in advance, according to the standard practice,and for the sake of clearness, the control circuits for these relays are not shown in Figure 2, as they form no part of my invention.V It is deemed sul-lil cient to say that the relay HR is deenergized whenever the first track section in advance is.

occupied,-that the relay DR is deenergized whenever either of the next two track sections in advance iscccupied and that the regroups similar to those described in connec-Y tion with the train carried apparatus of Fig. 1. These relays are designated in Fig; 2 by the reference' characters` 11A-11,'22A-22,

' SSA-33 and 44A-44- These relays are ,ar-

ranged in groups and connected by circuits identically the same as described for the sev eral groups of relays ofthe Fig. l, except there is no relay in Fig. 2 correspondlng to..

the relay 5A in Fig. l. Y

The approach energizing relay AP as stated aboye is normally deenergized Vand is.

supplied with energy whenever the track relay TR is shunted. The circuitqforthe relay: AP is also controlled bythe traliic controlling relays -DR, ADR andfalso.. bythe groups of relays. One'circuit for relay Al? may be traced from the positivel terminal'B, through back Contact of the 'arinature 57, line wire 58, winding of. thelrelay AP, front contact of armature 59 of the CT relay,vwire 60, frontv contact-of armature 6l of relay HR, front contact of armature 62 ofrelay DR. front Contact of armature@ of relay ADB, wire'64, back Contact of the armature G5 of the relay 4,4 and tothe negative termi' nal C. In the event thatI the relay HR is energized and relay DR' deenergized, then Vthe circuit for the relay AP iscompleted through back Contact of the armature 62, wire 66, back Contact 67 ofthe relay 22, and to the common terminal C. VAgain in the event relays HR and DR are energized and relay ADP.- deenergized, then thc circuit for the Y relay AP is Completed through a back con:-

tact ofthe armature wire 68,1back conf tact of the armature 69 of the reiay and te commen terminal. C. It will be observed that when the relay AP becomes energizedL to pick up its arniature 54,-the'circuit to the rcla y C'l is open and that thc relayC'l` becomes deenergized, and-thatthe deenergizing of relay CT vopens the circuit to the re-v lay AP at theY front Contact of the ar1na` ture 59.L It follows that-wlieneyerthe circuit for relay AP is complete there will be an alternate energizingandfdeenergizing of the relays AP and CT.; Inasmuch as the energizing and deenergizing of the relay CT periodically'interrupts the circuit'to the primary 50 of the track transformer T, this above action ofthe relays AP'and CT results in the'coding ofthe alternating cur-v rent Vsup-plied to the track rails X and Y. The

natural period of operation of the relay CT and AP is so chosen that they will complete a cycle of being energized and deenergized at thc rate of 180 times .per minute'.

`llachrelease and picking up of the'relay CT is counted on thc chain of relays 11A to 44 inclusive in'the following manner. The first deenergization of the relay CT: energizes the relay 11A byv current from thepositivo terminal B throughthe back-contact of the armature 7 0, Wire 7l, winding of the relay 11A and to the negative Vterminal C. The

relay lA is made slo\vv-releasing so that it will* remain energized as long as the relay CT 'continuesto be operated at the rate of 180 times per minute. On the next picking up of the relay GT, the relay l1 iscnergized through the front `Contact ofv armature T0 and the front contact of the armature 72 of the relay 11A. Relay 1l is made slow-releasing, and it will also remain energized as long as vrelay CT continues to operate at the ratek of 180'timeslper minute. On the' second de- Y energization of the relay GT, .the relay 22A isenergized through the back Contact of armature- 70, the front contact of the armature 73 and a back contact of the armature 74 of the'relay` 22. On the next picking up ofthe Y relay GT, therelay22'becomes energized by the circuit that includes the front contact of the armature '75 and the two coils of the relays'QQA and22 in series. on the thirdk operation of the GT-relay, the next two relays 33A'and 33 are picked up and then they are retained energized as long as the relay Il1 remains up. On thev fourth op-vV eration of the CT relay, the relays 44Aand 44 are picked up. Assuming relays HR,

DR and ADR areall energized. then as the relay 44 picks up, the circuit to the approach I energizing relay AP is opened at the back In like manner contactl of the armature 65 and the relay CT remains up due to thefact-that the'relay 44 acts faster than the relay AP vand the armature 65 of relay 44 is up to open the circuit of AP before the relay AP lifts its armature 54- suiiciently to open the circuit of the relay CT.

At the expiration of the release period of y f f the relay 11A, its armature 72 drops to open v the circuit to the relayll. At the expiration of the release period of the relay 11, its-ar mature dropstocut off energy to fthe several groups of relays including the relay 44. Assoon as this relay 44 becomes dener` gized-toY again close the circuitfor the relay of 0.5 second duration.

AP at its arma-ture 65, the operation of reenergizing the chain of relays'llA to 44 is again repeated. By making the summation of the release time of the relaysV 11A, 1l and 44 equal to 0.5 second plus the normal period of a. short impulse, it follows that the duration of the long impulse during which timev current is supplied to the rails X and Y is equal to this total time, and which it will be 'l recalled is somewhat greater than the time a. long impulse ofl 0.5 second duration and,

that this group of impulses will be consecutively repeated. In the event the traiiic conditions are such that the relay ADR is down-- that is to say, the iirsttwo track sections in advance are unoccupied but the third track section in advance is occupied then the energizing of the group of relaysof Fig. 2 will be stopped vat the relay 33, and inasmuch as then the relay 33 isenergized, the circuit to the relay AP is opened at the back contact of the armature 69. Under this condition, the code of the track circuit current will consist of a kgroup of .three com-plete cycles of short impulses followed by a long impulse Again if traflic conditions are such that the relay DR is down-'- that'is to say, the first track section in advance is unoccupied but the second track section in advance occupied1 then the operation .I of energizing the group of relays will be stopped at the relay 22, inasmuch as the circuit to the relay AP will now be opened at the back Contact of the armature 67, and in this case the code of the track circuit current consists of a group of two cycles of short impulses followed by a long impulse. Again if the traiiic conditions are such that the relay HR is down, then the relay AP remains deenergized and non-coded current is supplied to the rails X and Y.

Assuming that a. train equipped with the apparatus of Fig. l enters the track section of Fig.2 at a time when traffic conditions permit the relays HR, DR and ADR to be energized, that is, at least three track sections in advance are unoccupied, the' alternating current supplied to the track rails X and 'Y under this condition will be a code that consists of a group of four impulses followedY by a. long impulse. .From the foregoing description, it is recalled that a code of four short impulses and a long impulse will operate the group of relays that closes the circuit to the trattic governing relay A' on the train and bring about the display of the cab signal 45 which we shall'term a proceed signal.

Assume that the traiiic conditions in advance of the section are such that the relay ADR Ais deenergized while relays -HR andV DR are energized, that is, the irst two sections in advance are unoccupied and the third section in advance occupied, so that the code for the track circuit consists of a group of three short` impulses and a long impulse. As was previously pointed out, this code 0perates the group of relays that results in the'v traflic governing relay R on the train being energized and the cab signal 46 displayed, which signal we shall term approach restricted. Again if the first section in advance is unoccupied and the second section' in advance occupied sot-hat the relay DR is 'downf lith relay HR -deenergized`, then the circuit for the relay AP is open and the current supplied to the rails X and Y is non-coded. Vith non-coded alternating current flowing in the rails, the armature 9 of the master relayA lWR is held steadily in the right-hand position. Under this condition, the train carried relays 1A and l' were released at the expirationof their release period and the'chain of relays on the train is deenergized, and in turn, the trafiic governing relays L, R and A deenergized. n tion results in the cab signal 40being displayed which we' shall term a slow signal.

In the event a train already occupies the section of Fig. 2 as a second train enters the section, then the iirst train will shunt the track circuit current away from the following train. As the induced current in coils 14' and 15 dies away the armature 9 is moved tothe left-hand and it thenremains in this position as long as no current flows in the rails. As previously pointed 'out this conditionresults in the display of the slow cab signal 40. Y

To sum up the operation of the apparatusI of Figs. l and 2, a proceed cabsignal is dis played only in the event a definite code consisting of a! group of four complete cycles of short impulses followed by a long impulse. is consecutively applied tothe railsf-that an approach restricted indication is estab lished on the train in' the vevent that traffic conditions are such that a code consisting of aV group of three short impulses and a lone; impulse is consecutively supplied to the rails. Agaim'an approach cab signal is display-ed Under This condi- -1 CCI in the event the code consists of two short impulses and a long impulse, and a slow cab signal is displayed whenever non-coded current is supplied to the rails or whenever the track circuit is shunted.

1Whilethe track apparatus as vdescrihed in 2 will provide the proper codes re-V quired, it will be understood that my iur-cntion is not limited to this one form of codo transmitting means and that other means for transmitting the above code maybe equally as well employed such for example as the motor driven cam type of code transmitter.

In the form ot the train carried equipment disclosed in Fig. 3, the master relay MR is provided with a second armature 77, the heel of which is connected to positive battery terminal B. The normal and reverse contacts of the arma-ture 77 are connected to theV outside terminals of the primary 78 ot' a decoding transformer DT which has a center tap that is connected to the negative terminal C. The secondary 7 9 of the decoding transtornier'DT is provided with a secondary circuit composed of reactor 8,0 and a condenser Sl'in series. A full wave rectifier 82 is connected across a portion of the reactor 8O and the output terminals of the rectifier 82 are connected to the winding of the L relay. T he i parts ofthis secondary circuit are so proportioned tnat the relay L responds when the master relay MR is operated on 180 cycle current. The slow-release period of the relay L in this form of the train apparatus is of Jsuliicient duration that its armature 83 is retained lifted during the long impulse, that is, it is greater than 0.5 second duration. It follows that whenever the master relay MR is operated on any of the codes cited previously in this description the relay L is retainedl energized, while whenever the relay MR is not operated on 180 cycle current the relay Lis deenergized and its armature 83 drops.

|The operation of energizing the chain of relays 1A to 4A inclusive of Fig. 3 is the same as that described in connection with the Fig. l. However,the control of the traine governing relays in the Fig. 3 is different Vfrom that described for the Fig. l.

In Fig. 3 a code consisting of a group oi three cycles of short impulsesseparated from the preceding and succeeding groups by a long impulse results in the relays 1A to 3 being energized during the three short impulses and then deenergized during ythe long impulse. lVit-h all the relays energized the iront contacts of the respective armatures 24, 8'? and 89 are closed and thus as the relay 1A becomes deenergized that its armature 2l engages its back Contact, current is momentarily supplied to the tratlic governing relay A from the positive terminal B through the back contact'of armature' 2l, the front contacts of the respective armatures 24, 87 and V39, the back Contact oic armature 92 of the relay 4A, windingV of relay A and to the negative terminal C.

As stated in connection with Fig. l, the relayl A has a slow-release period greater than the time consumed by the group of short impulses plus the time of thel long impulse and thus this relay A will remain energized as long as this code persists. W ith relay A energized, then the circuit to the proceed cab signal 45 is closed as follows: positive terminal B, front contact of armature 83 of the relay L, wire 88, front contact of the armature 89 of the relay A, wire 90, proceed cab signal 45 and to the negative terminal C.

l/Vith a code'consisting ota group of two short impulses separated from the preceding and succeeding groups by a long impulse, the relays 1A to 2 ot the Fig. 3 are energized during the two short impulses and then all deenergized during the longimpulse. I Under this condition, a circuit to the traliic governing relay R is completed during the inter` val that the relay 1A is down and the relays l and 2 are still up.v This circuit for the re-4 lay R maybe traced `from t ie positive terminal B through the back contact of' the armature 2l, front contacts of the armatures 24 and 8'? ,and the bach contact ot the armature 39. As stated in connection with Figui, the relay R has a slow-release period greater than the time consumed by the short impulses, plus that consumed by the long impulses and thus the relay Ris retained energized' as long as this code persists. With relay R energized then the circuit is closed to the approaching restricted cab signal 46 as follows: positive terminal B, front contact of armature 83, wire 88, bach contact of armature 89, front contact of armature 91, cab signa-l 46 and to negative terminal C. In the 'event the 180 impulses are not arranged in groups which lare separated by a long impulse, the relay L of Fig. 3 will remain energized but'the relays R and A are both deenergized due to thefact that the relay 4A is retained energized after the fourth impulse. VVV ith all the relays 1A to 4A inclusive energized, then the circuit to relay A is open at the back contact of armature 21 and the back contacty oi armature 92 and the circuit-to the relay R is held open at the back conta-ct of armature 2l and at the bach Contact of armature Y39. Under this condition where relay L is energized and both relays A and R deenergi'zed, a circuit is closed to the approach signal light 4'? which circuit includes the front contact of the armature 83 and the back contacts of the armatures 89 and 91 as will be readily understood in the Fig. 3. Inv the event the master relay MR is not operated on code and the relay L is down, then the circuit to the slow cab signal 40 is complete as will be evident by an inspection of the Fig. 3. V Y

To sum up the operation of the apparatus of Fig. 3, the proceed cab signal is displayed when the code of the track circuit consists of a group of three short impulses separated from the preceding and succeeding ftraclr circuit or when the track circuit is vrelay 83.

groups by a long impulse. The approach A restricted cab signal i6 is displayed When the code consists of tivo cycles ot short impulses and a long impulse. rlhe approach cab signal 47 is displayed When the code consists of short impulses only, and the slow cab signal .t0 is displayed when non-coded current flows in the shunted.

The track apparatus to coordinate with the train carried apparatus oit Fig. 3 would deviate from that shown in the Fig. 2only in the manner oit controlling the approach energizing relay AP through the control relays HR, Dit and ADR. 'Io provide for a code consisting oit three short impulses between successive long` impulses in response to `relay AP that includes the front contacts of the armatures 6l and 62 and the bach Contact ot the armature 63 be connected to the negative terminal through the back contact of the armature 67. Again in Fig. 2 for the apparatus to supply a code consisting of short impulses only, under caution conditions, it requires that the circuit for the relay AP that includes the front contact of armature 6l and `the baclr contact or" armature G2 be connected directly to the negative terminal C.

Again referring to the Fig. 3, if a second secondary circuit for the decoding transformer DT be provided and this second secondary circuit be tuned to a code Jfrequency lother than the 180 cycles per minute, say to a frequency oit l2() cycles per minute, it is apparent that this second secondary circuit could control a relay similar to the relay L and this additional relay could then be used to control additional signals it such Were required.

It is apparent from the Jforegoing description that the apparatus of my invention provides a system that is practically immune from false proceed indications due to shock excitation when operating on electric roads or when operating over alternating trackcircuits, and that a large number of distinctive indications can readily be provided Without a great outlay of apparatus.

Although I have herein shown and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

l. In combination, a signaling circuit, a plurality of inter-inclusive groups ofk sending relays associated With said signaling circuit for supplying said circuit With a plurality of different codes ot current impulses by operating the relays of the selected group in a cyclic order, a plurality of inter-inclusive groups ot receiving relays also associated with said circuit adapted to be selectively voperated in a cyclic order by the differont codes ot current impulses, and a plurality of signalsA selectively controlled by the said groups ot receiving relays. Y

2. In combination, a signaling circuit, a plurality of inter-inclusive groups of sending relays associated with said signaling circuit, means for operating the relays of a group in a cyclic order to supply the signaling circuit with a respective code of current impulses, a plurality of inter-inclusive groups ot receiving relays also associated With said signaling circuit, means for operating in a cyclic order the relays of a group of receiving relays in response to the code supplied by a respective group of sending relays to the signaling circuit, and a plurality ot signals selectively controlled by the said groups of receiving relays.

3. In combination, a signaling circuit, a

plurality of inter-inclusive groups of send-A ing relays associated With said signaling circuit, means for operating the relays of a group in a cyclic order to supply the signaling circuit with a respective code of current impulses, a plurality of inter-inclusive groups vot receiving relays also associated with said signaling circuit, means for operating in a cyclic order the relays of a group of receiving relays in response to the code supplied by a respective group of sending relays to the signaling circuit, and means controlled from a distant point to select the di'erent groups otl sending relays.

4. In combinatioma signaling circuit, a code transmitting means adapted to supply to said signaling circuit code impulses of alternating current each off which has apredetermined period of duration, a slow-release device having a release period greater than the said predetermined period, and an automatic means to periodically render said slow-release device eiective to retain said code transmitting means in its current supplying condition during its release period to supply said signaling circuit with a code having a group of current impulses separated Jfrom the preceding and succeeding groups by a. relatively longer impulse of current.

5. In combination, a signaling circuit, a code transmitting means adapted to supply to said signaling circuit code impulses of alternating current each of Which has a predetermined period of duration, a slow-release device having a release period greater than the said predetermined period, an automatic ,meansto periodically yrender said slow-release device effective to retain said code transmitting means in its current supplying condition during its release period to supply said signaling circuit withA a code having a group oi alternating current impulses separated from the preceding and succeeding groups by a relatively longer impulse or alternating current, and means controlled from a distant point to select the number or' impulses 1n a group.

6. In combination, a signaling circuit, a code transmitting means adapted to supply to said signaling circuit code impulses of alternating current each of which has a predetermined period of duration, a plurality of groups of relays each group of which has a release period greater than the said predetermined period, a circuit including an armature operated by the code transmitting means to energize in cascade the relays of each of said groups, means rendered elective by the energizing of the last relay oi' a group to deenergize the relays of the group and to retain the code transmitting means in its current supplying condition during the release period of said relays to supply said signaling circuit with a code having a group of alternating current impulses separated from the preceding and succeeding groups by a relatively longer impulse of alternating current, and means controlled from a distant point to select the groups of relays.

7. VIn combination, a conductor, a code transmitting device, a circuit including a source of alternating current and an armature operated by said code transmitting device to supply code impulses of current to the conductor, a plurality of inter-inclusive groups oi relays, a circuit including an armature operated by said code transmitting device to energize in cascade the relays of each of said groups, means rendered active upon the energizing of the last relay of a group to deenergize the relays of the group after a predetermined interval, and means controlled by said groups of relays to control the operation of said code transmitter.

8. In combination, a track section, a code transmitting device, a circuit including a source of alternating current and an armature operated by said code transmitting device to supply code impulses of current to the rails of the section, a pair of slow-releas` ing relays, a plurality of inter-inclusiye groups of relays each including the said slow-releasing relays, a circuit including an armature operated by the code transmitting device to energize in cascade the relays of each group, means rendered active upon the energizing of the llast relay of a group to deenergize concurrently at the expiration of the release period of said slow-releasing relays the remaining relays of the group, and means controlled jointly by traino conditions and the groups of relays to control the operation or the codetransmitting device.

9. i train control system, including a plu lrality oftrain carried quick acting relays capable oi being arranged into different groups,

a. pair of slow release relays on thetrain, a

code following relay adapted to energize the of impulses trom the preceding and succeed` ing groups by a current impulse of relatively longer duration, and a plurality of train caried signaling circuits selectively controlled by said groups of relays.

10. A train control system, including a track section, a vehicle to travel over said track section, a trackway armature, means to periodically yoperate the armature at a given rate, a circuit means governed by said armature to supply code impulses of current to said track section in step with its operation, a plurality of different groups of trackway relays with the relays of each group adapted to be energized successively as said armature is operated and to hold said arma. ture stationary when all of the relays of the group are energized, means to deenergize the relays of a group concurrently at the end of a predetermined stationary period and thereby again permit the operation of the armature, means to select the group of relays in accordance to traliic conditions, a code following relay on the vehicle responsive to `the current impulses supplied to the track section, and aplurality ot signaling circuits'v on the vehicle selectively controlled by the code following relay.

11. A train control system, including a track section, a vehicle to travel over the secs tion, a trackway armature, means to periodically operate the armature at a given rate, a circuit means governed by said armature to supply code impulses of current to said track section in step with its operation, a plurality of different groups of trackway relays with the relays of each group adapted to be energized successively as said armature is operated and to hold said armature stationary when all of the relays of the group are energized, means to deenergize the relays of a i en group at the end of a predetermined stationary period and thereby again permit the operation Vof the armature, means to select the group of relays in accordance with traffic Y conditions and thereby establish diferent codes of current impulses, a code following relay on the vehicle, a plurality of relays on the vehicle adapted to be energized successively in response to the operating of the code following relay by the current impulses supplied tothe track section and to be deenergized during the stationary period of trackway armature, and a plurality of signaling .devices on the vehicle selectively controlled in response to the energizing and denergizing of the vehicle relays.

In testimony whereof I affix my signature.

GEORGE W. BAUGHMAN. 

